In an attempt to reduce hydrocarbon emissions, environmental regulations in certain areas of the country require that gasoline vapors displaced from vehicle fuel tanks during refueling are to be recovered to prevent their escape into the atmosphere. Accordingly, nozzle assemblies incorporating vapor recovery systems have been designed to comply with these regulations. As is known in the art, many of these nozzles have a vapor-recovery system for receiving the vapors displaced from the fuel tank and storing them in a service station's underground hydrocarbon storage tank. These nozzles normally include a discharge spout that extends into the mouth of the fill pipe of the fuel tank and a vapor-recovery shroud that fits in sealing engagement with the mouth of the fill pipe during refueling so as to receive the vapors displaced from the fuel tank. With this arrangement, vapors in the fuel tank are displaced from the tank as fuel is pumped into the tank. The displaced vapors will then flow by way of the shroud into a vapor-recovery passage in the nozzle and from there by appropriate means to the hydrocarbon storage tank.
A problem that commonly arises in the use of vapor-recovery nozzles is the occurrence of fuel spills from the discharge spout of the nozzle. When the nozzle is shut off at the termination of vehicle refueling, some fuel usually remains in the discharge spout of the nozzle, and upon removal of the nozzle from the fill pipe, the fuel remaining in the discharge spout may spill from the spout, striking the vehicle, the operator of the nozzle or the ground. Any fuel that does not spill from the spout may evaporate in the spout when the nozzle is not in use and stored in the fuel dispenser. When fuel spillage occurs either by fuel spilling from the discharge spout or by fuel vapors escaping therefrom, hydrocarbon emissions will be produced, offsetting the gain made towards the recovery of escaping fuel vapors by the use of vapor-recovery nozzles.
Vapor-recovery fuel dispensing nozzles that are currently available, such as those described in U.S. Pat. Nos. 4,060,110 (Bower) and 4,058,149 (Hansel) are not designed to eliminate the heretofore-described problem. Accordingly, the present invention is directed to a valve means for sealing the outlet end of a discharge spout of a vapor-recovery fuel dispensing nozzle so that fuel and fuel vapors remaining in the discharge spout subsequent to refueling are prevented from escaping therefrom.